/**
* @file sha2.h
*
* @brief SHA-224 and SHA-256 cryptographic hash function
*
* Copyright (C) 2006-2010, Brainspark B.V.
*
* This file is part of PolarSSL (http://www.polarssl.org)
* Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
*
* All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifndef POLARSSL_SHA2_H
#define POLARSSL_SHA2_H

#include <string.h>

#define POLARSSL_SHA2_C	1
//#define POLARSSL_SELF_TEST	1
#define POLARSSL_ERR_SHA2_FILE_IO_ERROR -0x0078 /**< Read/write error in file. */
#define SHA256TYPE	0
#define SHA244TYPE	1
/**
* @brief SHA-256 context structure
*/
typedef struct
{
    unsigned long total[2]; /*!< number of bytes processed */
    unsigned long state[8]; /*!< intermediate digest state */
    unsigned char buffer[64]; /*!< data block being processed */

    unsigned char ipad[64]; /*!< HMAC: inner padding */
    unsigned char opad[64]; /*!< HMAC: outer padding */
    int is224; /*!< 0 => SHA-256, else SHA-224 */
}
sha2_context;

#ifdef __cplusplus
extern "C" {
#endif

/**
* @brief SHA-256 context setup
*
* @param ctx context to be initialized
* @param is224 0 = use SHA256, 1 = use SHA224
*/
void sha2_starts( sha2_context *ctx, int is224 );

/**
* @brief SHA-256 process buffer
*
* @param ctx SHA-256 context
* @param input buffer holding the data
* @param ilen length of the input data
*/
void sha2_update( sha2_context *ctx, const unsigned char *input, size_t ilen );

/**
* @brief SHA-256 final digest
*
* @param ctx SHA-256 context
* @param output SHA-224/256 checksum result
*/
void sha2_finish( sha2_context *ctx, unsigned char output[32] );

/**
* @brief Output = SHA-256( input buffer )
*
* @param input buffer holding the data
* @param ilen length of the input data
* @param output SHA-224/256 checksum result
* @param is224 0 = use SHA256, 1 = use SHA224
*/
void sha2( const unsigned char *input, size_t ilen,
           unsigned char output[32], int is224 );

/**
* @brief Output = SHA-256( file contents )
*
* @param path input file name
* @param output SHA-224/256 checksum result
* @param is224 0 = use SHA256, 1 = use SHA224
*
* @return 0 if successful, or POLARSSL_ERR_SHA2_FILE_IO_ERROR
*/
int sha2_file( const char *path, unsigned char output[32], int is224 );

/**
* @brief SHA-256 HMAC context setup
*
* @param ctx HMAC context to be initialized
* @param key HMAC secret key
* @param keylen length of the HMAC key
* @param is224 0 = use SHA256, 1 = use SHA224
*/
void sha2_hmac_starts( sha2_context *ctx, const unsigned char *key, size_t keylen,
                       int is224 );

/**
* @brief SHA-256 HMAC process buffer
*
* @param ctx HMAC context
* @param input buffer holding the data
* @param ilen length of the input data
*/
void sha2_hmac_update( sha2_context *ctx, const unsigned char *input, size_t ilen );

/**
* @brief SHA-256 HMAC final digest
*
* @param ctx HMAC context
* @param output SHA-224/256 HMAC checksum result
*/
void sha2_hmac_finish( sha2_context *ctx, unsigned char output[32] );

/**
* @brief SHA-256 HMAC context reset
*
* @param ctx HMAC context to be reset
*/
void sha2_hmac_reset( sha2_context *ctx );

/**
* @brief Output = HMAC-SHA-256( hmac key, input buffer )
*
* @param key HMAC secret key
* @param keylen length of the HMAC key
* @param input buffer holding the data
* @param ilen length of the input data
* @param output HMAC-SHA-224/256 result
* @param is224 0 = use SHA256, 1 = use SHA224
*/
void sha2_hmac( const unsigned char *key, size_t keylen,
                const unsigned char *input, size_t ilen,
                unsigned char output[32], int is224 );

/**
* @brief Checkup routine
*
* @return 0 if successful, or 1 if the test failed
*/
int sha2_self_test( int verbose );

#ifdef __cplusplus
}
#endif

#endif /* sha2.h */
